A dental implant (hereinafter simply referred to “implant”) used for implant treatment is made up of a fixture (implant body, for example, made of titanium) to be embedded into an alveolar bone at which a tooth is missing, an abutment coupled to and supporting the fixture, and a superstructure (artificial tooth crown) attached to the abutment. In the implant treatment that uses this type of implant, it is very important to accurately drilling a guide hole, into which the fixture is to be embedded, in the alveolar bone (see JP-A-2001-170080, for example).
Implant treatment can be categorized into two types: prosthetically oriented treatment (top-down treatment) and exist-bone orientated treatment. In the former, top-down treatment, a mockup (full-scale plaster model) of a tooth and an alveolar ridge of a patient is created. The mockup is mounted to an articulator in order to determine the geometries and position of a functionally and aesthetically optimized prosthesis (superstructure). Based on the determination, the position at which the fixture is to be embedded is decided. In the latter, exist-bone orientated treatment, a surgically and anatomically optimal position at which the fixture is to be embedded is determined based on the condition of the alveolar bone (the width, thickness, and density of the alveolar bone, the course of the nerve, or other factors) of a patient.
Currently, CT-based simulation software may be used for determining a prosthetically (functionally and aesthetically) desirable position, at which the fixture is to be embedded, in consideration of the condition or other factors of the alveolar bone of the patient. In addition, a stent that contains a contrast medium may be used in CT scanning in order to display onto the mockup the position, at which the fixture is to be embedded and which is determined on a CT display.
When a guide hole into which a fixture is to be embedded is drilled in an alveolar bone of a patient, three-dimensional positioning and orientation of the drill in the mouth of the patient are required. However, it is quite difficult to accurately drill a guide hole by freehand at the position the fixture should be embedded by looking at the CT display or the mockup. Therefore, various jigs, i.e., surgical guides, have been devised.
A typical example is a surgical guide that has a metallic guide ring for guiding a drill to the position at which the fixture is to be embedded. When a drill is placed into a hole in the guide ring and inserted along the hole in the guide ring, the drill is guided such that a guide hole is formed at the position the fixture should be embedded.